1. Related Technical Fields
Related technical fields include map updating systems that update a part or all of the map data that is stored in a navigation apparatus, or the like, to new map data that is based on updated data.
2. Related Art
In recent years, navigation apparatuses that carry out travel guidance for vehicles and enable drivers to easily arrive at a desired destination are frequently mounted in vehicles. Throughout the application, the term “navigation system” denotes an apparatus that detects the current position of a vehicle by using a GPS receiver or the like, and displays map data that corresponds to this current position on a monitor; the map data being acquired through a recording medium such as a DVD-ROM, an HDD, or through a network. In addition, the map data, which includes the current position of the vehicle, is read out from the recording medium, and based on the map data, a map image of the vicinity of the current position of the vehicle is rendered and displayed in a display apparatus. In addition, a vehicle position marker (location) is superimposed on the displayed map image, and either the map image scrolls depending on the movement of the vehicle or the map image is held stationary on the screen and the vehicle position marker moves. Thereby, it is possible to understand at a glance the location through which the vehicle is currently traveling.
New roads (newly constructed roads) are built every year all over Japan. In addition, existing roads are closed or the configurations of existing roads are modified. Therefore, the map data that is stored in the navigation apparatus must be updated at a certain time interval. The updating of the map data is carried out by purchasing a new DVD and using it to replace an old DVD, or overwriting the content of a HDD based on map data that is distributed from a map data distribution center or the like. Presently, the following two updating methods are used when the content of the HDD is overwritten.
In a first method, when there is an update related to a road or the like, incremental update data, in which only the modified portions of the roads have been updated, is generated at a map data distribution center. When there is incremental update data that is related to a particular area (for example, areas in the vicinity of a registered residence) for which updating appears to be necessary in each navigation apparatus, the map data is updated to the new map data by using this incremental update data (below, referred to as “incremental updating”) (refer, for example, to Japanese Patent Application Publication No. JP-A-2004-198841).
In a second method, periodically (for example, at one year intervals), comprehensive update data, in which map data for the entire country is updated by new map data that reflects the current road conditions, is produced by a map data distribution center, and the map data is completely updated to the new map data by using the comprehensive update data that has been produced (below, referred to as “comprehensive updating”).
With respect to incremental updating, the following plurality of types of updating methods are available in which the methods for acquiring the incremental update data that has been produced by a map data distribution center differ.
(1) An updating method in which incremental update data is acquired from a center by using an automobile communication module that is mounted in the vehicle in advance, and updating is carried out automatically when, for example, the ACC is turned ON, during a residence registration, or when setting a destination.
(2) An updating method in which the user carries out particular operations while a mobile telephone is connected to a navigation apparatus, thereby the incremental update data is acquired by using the communication function of the mobile telephone, and updating is carried out based on the acquired incremental update data.
(3) An updating method in which the user's PC or an operator downloads the incremental update data from a center through an internet line, and the downloaded incremental update data is recorded on a CD-R; the updating is carried out by inserting the recorded CD-R into the navigation apparatus and reading the CD-R.